It seems that the Obama administration was fearing to be duped by the Turkish premier Erdogan into a NATO Article 5 case of common defense. Severe attacks from Syria onto Turkish soil could trigger such a case. Erdogan had already claimed that some artillery shells that killed five people in the border town of Akçakale were fired by the Syrian army.
To prevent that Erdogan pulls off some Gulf of Tonkin incident a U.S. general was send out to preempt him:
It is not clear who is shooting shells from Syria into Turkey, the commander of the U.S. Army Europe and Seventh Army, Lt. Gen. Mark Hertling has said, private television channel NTV yesterday.
"We are not sure if these shells are from the Syrian army, from rebels who want to get Turkey involved in the issue or from the PKK [Kurdish Workers’ Party]," he said.
Translation: "Dear Recep Tayyip Erdoğan, don't even think of using some fake artillery incident or some similar stunt to draw us further into your war on Syria. Signed: Obama (+ Romney)"
It is obvious that Erdogan's neo-ottoman plan to take over Syria is in deep trouble. Assad will not be overthrown and with no international help coming Turkey has run out of options. For Erdogan the about only thing he can still do to prevent more damage of Turkley's position is to stop all transfer of weapons and personal to Syria and to thereby let the rebels run out of ammunition and money. The war would then die down. Erdogan would need to blame someone for the huge mistake he made with supporting the overthrow of Assad. He will have to fire his foreign minister Dovatogu and blame him for the mess he created with all of Turkey's neighbors.
The killing of the Lebanese Brigadier General Wissam al-Hassan has likely shut down most of the organized weapon transfer from Lebanon to Syria. Little seems to come from Jordan. Whatever is coming from Iraq seems to be no more than the usual local smuggling. The only big pipeline of weapons, which was organized by the dead U.S. ambassador Stevens, came from east Libya via Turkey into Syria. When that transfer route is blocked the end of the war on Syria will be in sight.